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ASUS Extreme N6600GT Silencer
Date: Nov 28, 2005
Author: Matt Beauvais
Introducing The N6600 GT Silencer

An unfortunate side effect of many of today's high-performing PC peripherals is significant heat output. The need to tame this heat has led to bigger, and unfortunately, louder cooling solutions, which is something we at HotHardware are very familiar with. With the number of fans we have in some of our test systems, you'd think we were trying to keep the fires of hell at bay. Our intentions aren't that heroic though, we're just after the same thing most of you probably are; a decent computer. Without any background noise, even a system that could be considered "mid-range" by today's standards can be quite loud. The quest for more exotic, quiet, and more efficient cooling solutions has certainly delivered some interesting designs.

Today, we'll be looking at ASUS' Extreme N6600GT Silencer, which is a silently cooled "mid-range" video card. One of the more popular cooler designs of today, is to have the hot air exhausted out of the back of the case through an additional PCI slot opening. This dual-slot design is far more efficient at dispersing heat than the use of a giant heat sink without a fan to remove heat. Not exhausting the heated air generated by a video card has a cascading effect on the rest of your hardware, which results in increased temperatures for every component. However, with a passively cooled video card, your system will certainly be quieter. Which is what this card is designed to do.

When testing the ASUS Extreme N6600GT Silencer, we'll be emulating a few various case configurations. A case with 3 fans, the same case with no fans, and even an open air test-bench (no case) will be tested as well. Game and cooling performance comes later.  But first let's have a look at NVIDIA's GeForce 6600GT specifications.

NVIDIA's 6600 GT Architecture
A plethora of features

  • Vertex Shaders
    Support for Microsoft DirectX 9.0 Vertex Shader 3.0
    Displacement mapping
    Geometry Instancing
    Infinite length vertex programs*
  • Pixel Shaders
    Support for DirectX 9.0 Pixel Shader 3.0
    Full pixel branching support
    Support for Multiple Render Targets (MRTs)
    Infinite length pixel programs*
  • Next-Generation Texture Engine
    Up to 16 textures per rendering pass
    Support for 16-bit floating point format and 32-bit floating point format
    Support for non-power of two textures
    Support for sRGB texture format for gamma textures
    DirectX and S3TC texture compression
  • Full 128-bit studio-quality floating point precision through the entire rendering pipeline with native hardware support for 32bpp, 64bpp, and 128bpp rendering modes


  • Full floating point support throughout entire pipeline
  • Floating point filtering improves the quality of images in motion
  • Floating point texturing drives new levels of clarity and image detail
  • Floating point frame buffer blending gives detail to special effects like motion blur and explosions


  • Advanced 16x anisotropic filtering
  • Blistering-fast anti-aliasing and compression performance
  • New rotated-grid anti-aliasing removes jagged edges for incredible edge quality
  • Support for advanced lossless compression algorithms for color, texture, and z-data at even higher resolutions and frame rates
  • Fast z-clear
  • High-resolution compression technology (HCT) increases performance at higher resolutions through advances in compression technology


  • Designed to enhance the performance of shadow-intensive games, like id Softwares Doom III


  • Designed for PCI Express x16
  • Supports for AGP 8X including Fast Writes and sideband addressing
  • Designed for high-speed GDDR3 memory
  • 128-bit advanced memory interface
  • 0.11 micron process technology
  • Advanced thermal management and thermal monitoring
  • Dedicated on-chip video processor
  • MPEG video encode and decode
  • WMV9 decode acceleration
  • Advanced adaptive de-interlacing
  • High-quality video scaling and filtering
  • DVD and HDTV-ready MPEG-2 decoding up to 1920x1080i resolutions
  • Dual integrated 400 MHz RAMDACs for display resolutions up to and including 2048x1536 at 85Hz.
  • Dual DVO ports for interfacing to external TMDS transmitters and external TV encoders
  • Microsoft Video Mixing Renderer (VMR) supports multiple video windows with full video quality and features in each window
  • Full NVIDIA nView multi-display technology capability


  • DVC color controls
  • DVC image sharpening controls


  • Windows XP
  • Windows ME
  • Windows 2000
  • Windows 9X
  • Macintosh OS, including OS X
  • Linux


  • Complete DirectX support, including the latest version of Microsoft DirectX 9.0
  • Full OpenGL, including OpenGL 1.5

* The operating system or APIs can impose limits, but the hardware does not limit shader program length.


A Closer Look & Package Contents

Keeping cool without a fan
How much copper does it take?


We know what some of you are thinking, "That's a big chunk of copper!".  Yes, the cooler on this card is big, and it's heavy, but it helps keep the GPU cool without making a sound. Another thing we're sure some of you are wondering, is whether or not this giant, heavy heatsink could damage the card or slot because of its weight. The answer to that question is most likely, No. It's a sturdy design, and ASUS has a reputation for using quality components. However, you should take caution when handling the card. Don't handle it by just the heatsink. You should also be careful not to grab the copper fins, as they're thin and it doesn't take much force to bend them.



On the backside of the card, you can see the copper ramsinks that are used to cool the card's RAM. With 256MB of GDDR3 installed, the memory can run at 1GHz without getting dangerously hot. The heatsink on the end, which contains the copper heatpipe, can be rotated upwards. This is a double edged sword, however. While in its upward state, it hovers over the CPU. This helps keep the card cool, as the fan on your CPU's heatsink will draw air through the copper fans. The problem with this, however, is that it could result in higher CPU temperatures because heated air will be blown over the CPU's heatsink. Assuming you don't have a highly overclocked CPU though, this shouldn't be too much of a problem.

Another important issue to consider, is whether or not the ASUS Extreme N6600GT Silencer will fit in your case. We're sure most cases should be able to accommodate this card, but we wouldn't go so far as to suggest a perfect fit in every enclosure.

When you do have the ASUS Extreme N6600GT Silencer in a case, you can be sure you're going to see a measurable increase in temperature. As we talked about earlier, with passive cooling and no exhaust fan, the heat generated by this card just sits inside your case, contributing to higher temperatures in the rest of your hardware. We know some of you are cringing at the moment, and we understand.  At HotHardware, we prefer cooler running systems too. But we'll discuss temperatures a little later in the article. 


Package Contents
All the extras

ASUS has provided a decent bundle to go along with their silently cooled 6600GT. Along with the standard drivers and operation manual, ASUS included a few games, as well as some handy applications. PowerDirector 3DE, Medi@Show, and ASUS DVD are all included, as well as Xpand Rally, the ASUS Bonus Gamepack(Chaos League, Second Sight, and PowerDrome), and Joint Operations: Typhoon Rising. A VGA to DVI converter, and an dongle that has connectors for Video, S-Video, RCA and YPbPr are included as well.


Test System & 3DMark05
Test system specifications
Building the beast

    Video Cards:

        Asus Extreme N6600GT Silencer
        XFX GeForce 6600 256MB DDR2
        HIS Radeon X700 Pro
        ATI Radeon X1300 Pro

    Additional Hardware:

        Athlon64 3000+ (Winchester)
        2x256MB Mushkin lvl2 PC3200

        2x512MB Mushkin Redline w/ F.E.A.R.
        Onboard Audio (7.1 AC97)
        120GB/160GB Western Digital Caviar ATA/100 HDs

Performance Comparisons with 3DMark05 v1.2.0
Starting out synthetic

3DMark05 is the latest installment in a long line of synthetic 3D graphics benchmarks, dating back to late 1998. 3DMark05 is a synthetic benchmark that requires a DirectX 9.0 compliant video card, with support for Pixel Shaders 2.0 or higher, to render all of the various modules that comprise the suite. To generate its final "score", 3DMark05 runs three different simulated game tests and uses each test's framerate in the final tabulation. Fillrate, Memory bandwidth, and compute performance especially all have a measurable impact on performance in this benchmark. We ran 3DMark05's default test (1,024 x 768) on all of the cards and configurations we tested, and have the overall results posted for you below.

Our first test might just set a precedent for the rest of our benchmarks. ASUS's Extreme N6600GT Silencer starts off with a solid lead over the competition here, besting every other card we tested. Though the 3DMark series of benchmarks are synthetic tests, a high score in 3DMark05 should equate to decent performance in most of today's Direct3D based games. There's only one way to find out though, so let's get to our actual in-game benchmarks...

Unreal Tournament 2004


Unreal Tournament 2004
The first contender

Unreal Tournament 2004


Epic's "Unreal" games have been wildly popular, ever since the original Unreal was released in the late '90s. Unreal, Unreal Tournament, and then Unreal Tournament 2003, rapidly became some of our favorites, for both benchmarking, and for killing a few hours when our schedules allowed it! The latest addition to the franchise, Unreal Tournament 2004, improves upon the graphics offered by the previous versions of the game. We used the retail version of UT 2004 to benchmark these cards at resolutions of 1024x768 and 1280x1024, without any anti-aliasing, and again with 4X AA and 8X anisotropic filtering enabled simultaneously.


It's hard to take down NVIDIA's GeForce 6600GT in this test, when comparing it to cards at a similar price point.  Even with a resolution of 1280x1024, with 4x Anti Aliasing and 8x Anisotropic filtering, the ASUS GeForce Extreme N6600GT Silencer gets 67.16FPS on average. The extra 128MB ASUS has added to this version of the 6600GT helps keep stable frame rates at higher resolutions, and with AA and AF applied.

Far Cry Performance

Far Cry
Jungle rendering performance

Far Cry


If you've been on top of the gaming scene for some time, you probably know that FarCry is one of the most visually impressive games to be released for the PC. Courtesy of its proprietary engine, dubbed "CryEngine" by its developers, FarCry's game-play is enhanced by Polybump mapping, advanced environment physics, destructible terrain, dynamic lighting, motion-captured animation, and surround sound. Before titles such as Half-Life 2 and Doom 3 hit the scene, FarCry gave us a taste of what was to come in next-generation 3D Gaming on the PC. We benchmarked the graphics cards in this review with the Ubisoft Regulator demo, at various resolutions without anti-aliasing or anisotropic filtering enabled, and then with 4X AA and 8X aniso enabled concurrently.

Both the ASUS Extreme N6600GT Silencer, and the HIS Radeon X700 Pro, put up some solid frame rates in Far Cry. Without the strain of Anti Aliasing and Anisotropic Filtering, the Asus Extreme N6600GT Silencer comes out ahead by about 8FPS at 1024x768, and by about 7FPS at 1280x1024. When both AA and AF are applied though, the performance gap shrinks to around 1-3FPS.

Doom 3 Performance


Doom 3
Scaring the competition

Doom 3


id Software's games have long been pushing the limits of 3D graphics. Quake, Quake 2, and Quake 3 were all instrumental in the success of 3D accelerators on the PC. Now, many years later, with virtually every new desktop computer shipping with some sort of 3D accelerator, id is at it again with the visually stunning Doom 3. Like most of id's previous titles, Doom 3 is an OpenGL game that uses extremely high-detailed textures and a ton of dynamic lighting and shadows. We ran this batch of Doom 3 single player benchmarks using the standard "Demo1" demo, with the game set to its "High-Quality" mode, at resolutions of 1024 x 768 and 1280x1024 without anti-aliasing enabled and then again with 4X AA and 8X aniso enabled simultaneously.


With OpenGL games generally favoring NVIDIA's architecture, it's little surprise that the ASUS GeForce Extreme N6600GT Silencer dominates the competition here. Doom 3 is perfectly playable at a resolution of 1280x1024 with no AA, and 8x AF applied. However, when using 4x Anti-Aliasing at the same resolution, the framerate drops down to an unplayable 28.3FPS. The 128-bit memory bus that is standard with all 6600GT's isn't meant for running games like Doom 3 at high resolutions with AA and AF.

Quake 4 Performance

Performance Comparisons with Quake 4
ASUS vs The Strogg

Quake 4
id Software, in conjunction with developer Raven, recently released the latest addition to the wildly popular Quake franchise, Quake 4. Quake 4 is based upon an updated and slightly modified version of the Doom 3 engine, and as such performance characteristics between the two titles are very similar.  Like Doom 3, Quake 4 is also an OpenGL game that uses extremely high-detailed textures and a ton of dynamic lighting and shadows, but unlike Doom3, Quake 4 features some outdoor environments as well. We ran this these Quake 4 benchmarks using a custom demo with the game set to its "High-Quality" mode, at resolutions of 1024 x 768 and 1280 x 1024 without anti-aliasing enabled and then again with 4X AA and 8X aniso enabled simultaneously.


With Quake 4 using the Doom 3 engine, the results we see are a surprise. NVIDIA continues to hold the lead, with the ASUS Extreme N6600GT Silencer holding a 20FPS advantage over the HIS X700 Pro in both resolutions with no Anti-Aliasing or Anisoptropic filtering. When AA and AF are used, the ASUS Extreme N6600GT Silencer continues to hold a comfortable 6-9FPS advantage over the HIS X700 Pro. Even though Quake 4 is more taxing on a graphics card than Doom 3, each of the 4 cards we tested are able to produce playable frame rates until additional pixel processing is used at the higher resolution.

Half-Life 2 Performance

Half-Life 2
Physics and Pixels

Half-Life 2


Thanks to the dedication of hardcore PC gamers and a huge mod-community, the original Half-Life became one of the most successful first person shooters of all time.  So, when Valve announced Half-Life 2 was close to completion in mid-2003, gamers the world over sat in eager anticipation. Unfortunately, thanks to a compromised internal network, the theft of a portion of the game's source code, and a tumultuous relationship with the game's distributor, Vivendi Universal, we all had to wait until November 2004 to get our hands on this classic. We benchmarked Half-Life 2 with a long, custom-recorded timedemo in the "Canals" map, that takes us through both outdoor and indoor environments. These tests were run at resolutions of 1024 x 768 and 1280 x 1024 without any anti-aliasing or anisotropic filtering and with 4X anti-aliasing and 8X anisotropic filtering enabled concurrently.

As Doom 3 and Quake 4 favor NVIDIA, Half-Life 2 has been known as a game that prefers ATI's brand of cards. Even so, the ASUS Extreme N6600GT Silencer continues to hold the lead. At 1024x768 with no Anti-Aliasing or Anisotropic Filtering enabled, the HIS X700 Pro and the ASUS Extreme N6600GT Silencer are within 5FPS of each other. However, when higher resolutions are used, especially when adding AA and AF into the mix, the ASUS Extreme N6600GT Silencer pulls ahead.

F.E.A.R. Performance



Performance Comparisons With F.E.A.R
Candy for the Mind and Eyes...

One of the most highly anticipated titles of 2005, Monolith's new psychological thriller F.E.A.R promises to be as thrilling to the mind as it is to the eyes. Taking a look at the minimum system requirements, we see that you will need at least a 1.7GHz Pentium 4 with 512MB of system memory and a 64MB graphics card that is a Radeon 9000 or GeForce4 Ti-class or better. Using the newly released single player demo, we put the notebook through its paces to see how it fared with a promising new title. Here, all graphics settings within the game were set to "Medium" and Trilinear Filtering was enabled. Benchmark runs were then completed at resolutions of 1024x768 and 1280x1024.


The beautiful, but power hungry shooter from Monolith, F.E.A.R. is the most demanding test we've put our graphics cards through. A resolution of 1024x768 with no Anti Aliasing or Anisotropic filtering is the only really playable setting in our testing. An average of 46FPS for the ASUS Extreme N6600GT Silencer might not even be considered enjoyable by some. We recommend lowering the resolution to 800x600 for a more fluid, albeit less visually pleasing, experience.

Overclocking and Cooling Performance

Overclocking with Quake 4
Pushing the limits

For our overclocking test, we enabled the hidden overclocking features built into the NVIDIA control panel by using Coolbits. When using NVIDIA's built in clock speed detector, the ASUS Extreme GeForce N6600GT Silencer was overclocked to 525MHz on the core, and 1.07GHz on the memory. This maximum clock speed detector is usually a bit conservative with it's overclock though, so we decided to see how far this card could actually go. We used ATI Tool's artifact detector for our test. While it's mainly for ATI cards, the artifact detector can be used with either ATI or NVIDIA cards as well, and will usually detect artifacts with it's testing, even before you'd notice them while gaming.

With the core set to 525MHz, and the memory set at it's default 1GHz, we ran ATI Tool for 15 minutes at stock settings to let the card heat up. Once the 15 minute mark was reached, we started raising the core by 5MHz about every 2 minutes until artifacts started to appear. At 540MHz, we had reached our limit. We would have liked to go higher, but the card wouldn't have any of that. We used a similar procedure when overclocking the memory. After letting the card heat up at 1.07GHz, we raised the memory by 10MHz every 2 minutes, until the test started displaying errors at 1.11GHz. This is much more impressive than our core overclock. We then set the card's core to 540MHz and the memory to 1.11GHz simultaneously and benchmarked for 25 minutes without an error. To give you an idea of the performance improvement that our overclock has brought, we decided to benchmark Quake 4 again at 1280x1024 with no Anti Aliasing, and 4x Anisotropic Filtering.

With an increase of 6.4FPS, Quake 4 becomes a little more playable at 1280x1024 with no AA and 4x AF applied. No matter how cool the core was, we couldn't get it to go past 540MHz without artifacts in ATI Tool. While NVIDIA's driver level artifact tester didn't report any problems until around 555MHz on the core, we opted to keep it at 540MHz for the sake of the card's longevity. ASUS does not provide any kind of overclocking with its warranty, so it's up to you to decide if the extra FPS is worth the punishment to your card. Those of you with minimal airflow in your case probably shouldn't overclock this card at all. That is only our recommendation, however, and each personal case will be different. It's really up to each individual consumer to weigh the risks against the benefits of overclocking with a passive heat sink. If you have any questions about overclocking, make sure to visit our PCHardware Forum for discussion on the subject.

Cooling Performance
Hot Hardware at HotHardware


Well, we have some interesting results here. The large heat sink that ASUS has used is able to disperse a great amount of heat. When having a small table fan near the card, blowing directly on the copper fins, the core only manages to reach a temperature of 62'C at full load. When moving the card into our Gigabyte 3D Aurora case, the load temps jump to around 78'C at full load. This is hot, but not nearly as hot as the results from our open air test. With our motherboard laying on our test bed, with no active airflow, the ASUS Extreme N6600GT Silencer jumps to 85'C. Now, you must remember that this is with the motherboard and video card out in the open. If you were to install this card inside a case with other components such as a motherboard, hard drive, and CPU installed, we could see the card reaching close to 90'C, possibly more.

We really can't stress enough how important airflow is in a computer case. The quest for a silent system will always stop short of complete silence. We have to recommend that at least one additional fan be installed in your case should you plan to use this card. Simply having hot air removed by the fan inside your power supply probably won't be enough to keep this card reasonably cool.

Final Thoughts and Conclusion

Looking back at what we saw throughout our testing and evaluation, we think the ASUS Extreme N6600GT Silencer is a good performer with a decent bundle. This card is not for everyone though. Even with the innovative heat sink, the core still gets very hot while running any kind of stressful test or game. Those of you who are not seeking a silent system might want to look for a more conventional 6600GT; one with active cooling. However, those of you who are on a quest for a quiet system should give this card some consideration.

ASUS has obviously worked hard on creating a silent, but relatively cool running card. This is a somewhat daunting task though. Those who would be most interested in this card, are the ones looking to remove all possible noise from their system. However, we don't recommend installing this card in a system with minimal airflow. There absolutely must be something to remove the heat from case that this card is installed in.  And the fan in your power supply might not be enough on its own, depending on the other hardware installed in your system and the temperature of your computer room.

Another potential problem has to do with the card's massive heat sink.  We're fairly certain it won't fit in some enclosures, although we did not have any problems fitting it into our case. We assume that ASUS has done some research into how well the Extreme N6600GT Silencer will fit into various computer cases, but we imagine there's more than a few that could have trouble with this card. If you have a large heat sink on your CPU, there could also be some problems when rotating the large heat sink.

Aside from the issues mentioned above, there's a lot to like about the Extreme N6600GT Silencer. ASUS has included some good software in its bundle, including PowerDirector and a few games. While Join Operations: Typhoon Rising might not be the most popular game, it's still a good showcase for the card's performance. During our overclocking adventures, we were a bit disappointed at the 40MHz overclock on the core. But the memory overclocked much better, reaching a lofty 1.12GHz. The increase in memory bandwidth helped smooth out frame rates at higher resolutions, and with Anti-Aliasing and Anisotropic Filtering enabled.

This card retails for around $220, and while it is a bit more expensive than a standard 6600GT, the extra 128MB of RAM, silent cooling solution, and ample software package nets the ASUS Extreme N6600GT Silencer an 8 out of 10 on our Heat Meter.

_Good software bundle
_Innovative Cooling
_Decent overclocker
_Still requires some sort of active airflow
_May not be compatible with all cases

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